In recent years, health and fitness practitioners have given greater and greater emphasis to core stability training for injury prevention, rehabilitation and performance enhancement. Sports strength and conditioning coaches and physiotherapists recommend that athletes perform regular core stability or trunk strength exercises to prevent injury. The rationale for such prophylactic training is that increased recruitment of the stabilizer muscles and increased strength of the prime movers will carry over into better posture and more control, both in daily life and in sporting movements.
The “core” actually consists of many different muscles that stabilize the spine and pelvis and run the entire length of the torso. These muscles stabilize the spine, pelvis and shoulder and provide a solid foundation for movement in the extremities. Core conditioning exercise programs need to target all these muscle groups to be effective.
The following list includes the most commonly identified core muscles as well as the lesser known groups. The goal of core stability is to maintain a solid, foundation and transfer energy from the center of the body out to the limbs. Muscles that accomplish this goal include:                Erector Spinae—This group of three muscles runs along your neck to your lower back.        Multifidus—these muscles extend and rotate the spine and are located under the erector spinae along the vertebral column.        External Obliques—located on the side and front of the abdomen.        Internal Obliques—located under the external obliques, running in the opposite direction.        Gluteus maximus, hamstring group, piriformis—located in the back of the hip and upper thigh leg.        Gluteus medius and minimus—located at the side of the hip        Hip adductors—located at medial thigh.        Hip Flexors—located in front of the pelvis and upper thigh. The muscles that make up the hip flexors include: the psoas major, illiacus, rectus femoris, pectineus and sartorius.        Rectus Abdominis—located along the front of the abdomen, this is the most well-known abdominal muscle and is often referred to as the “six-pack” due to it's appearance in fit and thin individuals.        Transverse Abdominis (WA)—located under the obliques, it is the deepest of the abdominal muscles (muscles of your waist) and wraps around your spine for protection and stability.        
In order to strengthen and condition the above, there are three major groups of exercises. The first group of exercises is that which focuses on the recruitment of the small deep-lying stabilizing muscles, transversus abdominis and multifidus, often taken from clinical Pilates. The second group is traditional dynamic strength exercises for the prime movers of the trunk, often performed on the floor. The final group is static bodyweight exercises focusing on developing stability and/or strength endurance in certain postures, and requiring co-contraction of the small stabilizer and larger mobilizer muscles, such as the popular ‘plank’ exercise.
An unfortunate reality is that the routine performance of the above core exercises leads to boredom. It has been said that ‘core exercises’ quickly become ‘bore exercises’! It takes self-discipline to do 20-30 minutes of the same exercises three or more times a week over a long period. As a consequence, adherence to a core-strengthening program can be challenging. The second limitation is physiological. The principles of specificity and progression apply to core work in the same way as they do to any other body training. It is quite common for an athlete to perform the same core routine over a long period and get very good at four or five movements or ‘holds’. But teach the same athlete a new core exercise and they will find it difficult, simply because it is a new stimulus. Clearly a need exists for a greater variety of such exercises in order to optimize the benefits of a core strengthening program.
Various apparatus have been developed to add greater variety to core exercise training, some offering greater challenges, and therefore benefits, to the user versus apparatus-free training. For instance, stability ball exercises also known as Swiss ball exercises, are believed to activate the trunk musculature to a greater extent than more traditional resistance exercises, thereby affording increased benefit to traditional dynamic strength exercises. The unstable surface of the ball is thought to provide a greater challenge to the core muscles than exercising on a stable surface. This is likely because the temporary loss of balance resulting from the unstable surface activates involuntary muscle contraction rather than a targeted muscle or muscle group performing a predictable voluntary movement to which the muscle can adapt through repetition. The subject invention facilitates core stability and strengthening using a wider variety of movements to maximize adaptations and muscle groups trained.